The disclosure relates generally to an apparatus for measuring an amplitude of an uneven measurement surface in industrial machines. More particularly, the disclosure relates to a system for measuring a deflection of a ripple spring in a stator core winding slot.
Deflection may be defined as the amount a structural component is displaced or deformed under a load. In many industrial machines, such as, for example, large scale generators, components such as ripple springs are compressed during installation. A ripple spring is an elongated substantially sinusoidal spring element that is placed between a stator core winding and a slot for the winding in a compressed state to secure the stator core winding in the slot. The deflection of a ripple spring is measured to ensure that the compression of the spring is within desired tolerances. A difference between a highest point of the spring and a lowest point of the spring is indicative of the amount of deflection.
Previous deflection measuring methods included manually measuring the relative positions of a number of points on the ripple spring using a pin gauge to determine the overall deflection of the ripple spring. This method required that a technician insert a single-pin gauge into each hole of a wedge that secured the ripple spring, one at a time. Once a displacement measurement was taken at each hole within the wedge, the engineer either had to record each displacement measurement or commit each measurement to memory. Then, the engineer manually calculated the difference between the displacement measurements of the pins to arrive at the deflection measurement. Generally, there are many ripple springs within a particular slot, and hundreds of slots within a single generator. Therefore, the amount of time spent on taking these measurements within a single generator was quite lengthy.
Another previous measurement method employed a deflection measurement system having a number of sensors between at least two alignment pins, wherein each sensor measured its own relative position when engaging a ripple spring. Subsequently, the deflection of the ripple spring was manually calculated by evaluating the differences in the relative positions of each sensor. However, this device was quite large as each sensor was connected to a processor that had to be carried by the engineer while taking measurements of the ripple spring, making the process time consuming and cumbersome. Additionally, the wiring of this device was expensive and made the device unwieldy.